I don't do near the amount of patterning I used to, and I don't load right now, either. However, I have seen vast differences from gun to gun, load to load, barrel to barrel, and choke to choke...with patterns. You can usually do a great bit of improvement to factory tube patterns with aftermarket tubes. They don't have to be the most expensive, either. Most will attempt to find a tube/load combo for their gun that gives them the 'best' pattern for their range, and they usually can find something that outdoes their factory tubes. I generally look for a tube that will give consistant kiling patterns with as many of the various shelss/shotsizes/speeds I might shoot in a season. That may mean I get a pattern not quite as good as with another tested tube for one load, but the same tube will pattern about the same %/densityy with several other loads. It makes life a little more simple for me, in the end. Some don't think it's worth giving that much thought. Sometimes, it's not. However, I've seen out of square chokes, choke tube threadings, bent barrels, etc. So regardless of whether or not you want aftermarket tubes, you need to ensure your barrel/chokes shoot and pattern where they are aimes, and then you can worry about fit vs point of impact....a bad choke/barrel/pattern will just ruin your fit and practice efforts, IMO. In my A5 that I shoot most of the time, Terror and Trulock tubes have proven the most versatile out of my Hastings barrel. They also prove consistant out of the invector plus barrel, though by not as much over the factory tubes as with the Hastings.